In this paper, waste polyacrylonitrile (PAN) fibers were used as raw material to obtain a hydrophobic felt-like flexible oil absorption material via immersion in 3-aminopropyltriethoxy silane coupling agent (KH-550) and low-temperature oxidation. Based on single-factor experiments, the optimal preparation process was determined: the KH-550 concentration was 0.05%, the immersion time was 50 min, and the oxidation temperature was 280 °C. The oil absorption material prepared under the optimal conditions could absorb 28.92 g g−1 of engine oil and owned a water contact angle of 142.2°. Subsequently, the morphology and structure of the oil absorption materials were characterized by scanning electron microscopy (SEM) and Fourier transform infrared (FT-IR). Characterization results showed that the addition of KH-550 guaranteed the formability of the material, and its forming mechanism was analyzed. Furthermore, oil retention capacity test and reusability test show that the oil absorption material has an outstanding oil retention rate of 96.2% and excellent recycling performance, proving its potential ability to clean up oil spill.